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		</style><hr><a name="_C_FIELDPLOT"><div style="background-color:yellow;font-family:courier new;"></a>CLASS <b>FieldPlot</b> EXTENDS <a href="Plot.html#_C_PLOT" style="font-face:arial;font-weight:bold;">Plot</a></div>
<i>(Defined in: jpgraph_scatter.php : 64)</i><table border=1><tr><td>&nbsp;<a href="FieldPlot.html" style="font-family:arial;font-weight:bold;color:darkblue;">FieldPlot</a>&nbsp;</td><td>&nbsp;<a href="Plot.html" style="font-family:arial;font-weight:bold;color:darkblue;">Plot</a>&nbsp;</td></tr><tr><td valign=top>&nbsp;<a href="FieldPlot.html#_FIELDPLOT_FIELDPLOT">FieldPlot()</a>&nbsp;<br>
&nbsp;<a href="FieldPlot.html#_FIELDPLOT_SETCALLBACK">SetCallback()</a>&nbsp;<br>
</td><td valign=top>&nbsp;<a href="Plot.html#_PLOT_HIDELEGEND">HideLegend()</a>&nbsp;<br>
&nbsp;<a href="Plot.html#_PLOT_SETCENTER">SetCenter()</a>&nbsp;<br>
&nbsp;<a href="Plot.html#_PLOT_SETCOLOR">SetColor()</a>&nbsp;<br>
&nbsp;<a href="Plot.html#_PLOT_SETCSIMTARGETS">SetCSIMTargets()</a>&nbsp;<br>
&nbsp;<a href="Plot.html#_PLOT_SETLEGEND">SetLegend()</a>&nbsp;<br>
&nbsp;<a href="Plot.html#_PLOT_SETLINEWEIGHT">SetLineWeight()</a>&nbsp;<br>
</td></tr></table>&nbsp;<p><div style="font-weight:bold;font-family:arial;font-size:100%;">Class usage and Overview</div>A variant of scatter plot is the so called <i>Field Plots</i> this is
basically a scatter plot where each scatter point is an arrow with a
direction between 0 to 359 degrees. This effectively allows the
visualization of 3 parameters at each point (x,y,angle). As an
additional bonus there is also possible to define a callback for each
scatter plot to also define the color for each point. <p> &nbsp;
<div style="font-weight:bold;font-family:arial;font-size:85%;">See also related classes:</div><a href="FieldArrow.html">FieldArrow</a> <p> &nbsp;<hr><span style="font-family:arial;font-size:120%;font-weight:bold;">Class Methods</span><hr><p>
<p>&nbsp; <p> &nbsp; <span style='font-size:110%;'><a name="_FIELDPLOT_FIELDPLOT"><div style="border-top:solid black 2pt;background-color:lightblue;font-family:courier new;font-size:90%;font-weight:bold;"><b><font color="#000000">
function FieldPlot($datay,$datax,$angles)</font>
</b></div></a></span>

<span style='font-family:arial;font-size:90%;'><i>Create an instance of FieldPlot</i></span><p>

<table cellspacing=0 style='border:black solid 1pt;' width=100%>
<tr><th width=25%>Argument</th><th width=15%>Default</th><th width=60%>Description</th></tr>
<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$datay</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Y-coordinate</td></tr>

<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$datax</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>X-coordinate</td></tr>

<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$angles</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Angle</td></tr>
</table>

<div style="font-weight:bold;font-family:arial;font-size:85%;">Description</div>Create a new instance of a field plot&nbsp;<br>

<div style="font-weight:bold;font-family:arial;font-size:85%;"><p>Example</div><span style="font-family:courier;font-size:85%;"><font color="#000000">
$fp = new FieldPlot($datay,$datax,$angle);</font>
</span><br>
<p>
<p>&nbsp; <p> &nbsp; <span style='font-size:110%;'><a name="_FIELDPLOT_SETCALLBACK"><div style="border-top:solid black 2pt;background-color:lightblue;font-family:courier new;font-size:90%;font-weight:bold;"><b><font color="#000000">
function SetCallback($aFunc)</font>
</b></div></a></span>

<span style='font-family:arial;font-size:90%;'><i>Specify callback for each arrow in the field plot</i></span><p>

<table cellspacing=0 style='border:black solid 1pt;' width=100%>
<tr><th width=25%>Argument</th><th width=15%>Default</th><th width=60%>Description</th></tr>
<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$aFunc</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Function name</td></tr>
</table>

<div style="font-weight:bold;font-family:arial;font-size:85%;">Description</div>Specify a callback that gets clled for each arrow in the field plot 
The callback should return an array with the elements
<ol>
<li> Color
<li> Size of arrow (in pixels)
<li> Arrow head size (as integer between0 and 9)
</ol>
&nbsp;<br>

<div style="font-weight:bold;font-family:arial;font-size:85%;"><p>Example</div><span style="font-family:courier;font-size:85%;"><font color="#000000">
// Gradient. Make the arrows red at the pole and colder (blue)
<br />// teh further we get from the pole
<br />function FldCallback($x,$y,$a) {
<br />&nbsp;&nbsp;&nbsp;&nbsp;$polex=4;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$poley=40;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$maxr = 3000;
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;// Size and arrow size is constant
<br />&nbsp;&nbsp;&nbsp;&nbsp;$size="";
<br />&nbsp;&nbsp;&nbsp;&nbsp;$arrowsize="";
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;// Since we have different scales we need the data points
<br />&nbsp;&nbsp;&nbsp;&nbsp;// to be of the same magnitude to give it a distance
<br />&nbsp;&nbsp;&nbsp;&nbsp;// interpretation.
<br />&nbsp;&nbsp;&nbsp;&nbsp;$x *= 10; 
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;// Colors gets colder the further out we go from the center
<br />&nbsp;&nbsp;&nbsp;&nbsp;$r = ($x-$polex*10)*($x-$polex*10)+($y-$poley)*($y-$poley);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$f = $r/$maxr;
<br />&nbsp;&nbsp;&nbsp;&nbsp;if( $f &gt; 1 ) $f=1;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$red = floor((1-$f)*255);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$blue = floor($f*255);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$color = array($red,0,$blue);
<br />&nbsp;&nbsp;&nbsp;&nbsp;return array($color,$size,$arrowsize);
<br />}
<br />
<br />// Setup the field plot
<br />$fp = new FieldPlot($datay,$datax,$angle);
<br />
<br />// Setup formatting callback
<br />$fp-&gt;SetCallback('FldCallback');</font>
</span><br>
<p> <hr> <p>